Merrimack River — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in the Merrimack River, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in the Merrimack River today is 19.4°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming. It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.
Water Temperature Chart Over the Last 30 Days
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| JUN 3 | 14.5°C | 18.5°C | |
| JUN 4 | 14.8°C | 18.5°C | |
| JUN 5 | 16.4°C | 18.5°C | |
| JUN 6 | 17.3°C | 18.5°C | |
| JUN 7 | 18.2°C | 18.5°C | |
| JUN 8 | 18.4°C | 18.5°C | |
| JUN 11 | 18.5°C | 19.4°C | |
| JUN 12 | 18.5°C | 19.3°C | |
| JUN 13 | 18.5°C | 19.3°C | |
| JUN 14 | 18.5°C | 19.2°C | |
| JUN 15 | 18.5°C | 19.2°C | |
| JUN 16 | 18.5°C | 19.1°C | |
| JUN 17 | 18.5°C | 19.1°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 0°C | 5°C | 9°C |
| February | 0°C | 5°C | 9°C |
| March | 0°C | 6°C | 11°C |
| April | 3°C | 10°C | 16°C |
| May | 8°C | 13°C | 21°C |
| June | 14°C | 19°C | 22°C |
| July | 17°C | 20°C | 24°C |
| August | 17°C | 22°C | 26°C |
| September | 11°C | 17°C | 22°C |
| October | 8°C | 14°C | 20°C |
| November | 3°C | 8°C | 16°C |
| December | 0°C | 5°C | 8°C |
Merrimack River: Water Temperature by Location
Merrimack River: Weather Forecast
June 9
June 10
June 11
June 12
Location & Local Information
Source Pemigewasset River-Winnipesaukee River juncture
• location: Franklin, Merrimack County, New Hampshire
Mouth Gulf of Maine
• location Newburyport, Essex County, Massachusetts
Length 117 mi (188 km)
The Merrimack River, which flows through New Hampshire and Massachusetts, is one of the largest rivers in the northeastern United States. The water temperature in the Merrimack River varies throughout the year, with cooler temperatures in the spring and fall, often ranging from 40°F to 55°F (4°C to 13°C). In the summer months, the water warms up to more comfortable temperatures, typically ranging between 60°F and 75°F (15°C to 24°C), making it more suitable for swimming.
Swimming in the Merrimack River is possible, particularly in areas with slower-moving water or designated recreational zones. Some parts of the river, especially around cities like Lowell and Lawrence, offer public access points where people can swim or relax by the water. However, caution is recommended, as the river's current can be strong in certain sections, and water quality can fluctuate, especially after heavy rainfall. While swimming isn't the most common activity in the Merrimack, it remains an option for those looking to cool off during the summer months. The river is also popular for boating, fishing, and kayaking, attracting a wide range of water enthusiasts.